This application relates to pneumatic material dispensers for granular chemicals, grain, seed, and the like of the type wherein material is dropped from the periphery of a rotating element into adjacent, axially spaced, material collecting passages of a collector and an air supply propels the material through discharge tubes attached to the collector for delivery to remote locations and, more particularly, to an improved air supply means and collector therefor.
In the referenced copending application, Ser. No. 681,307, there is taught a fluent material dispenser of the type described above, especially for use with a multiple row planter, which is provided with a precision metering device having a novel bucket. A major aim of that invention is to provide a uniform distribution of the material to each planter row from a central source. However, if the material and air are introduced to the collector at the same point, as in the prior art pneumatic material dispensers of Loesch et al., U.S. Pat. No. 3,637,108, Bauman et al., U.S. Pat. No. 3,860,146, and Schlegel, U.S. Pat. No. 3,731,842, and uneven distribution of material, particularly granular materials and grains, from the various discharge tubes can result. It is believed that this is due to the volume of air flowing through the tubes varying from tube to tube due to varying lengths thereof and causing a greater volume of material to enter passages having a greater air flow.
In the Smith et al. U.S. Pat. No. 3,093,296, in one embodiment, the material drops into the collector adjacent the air flow inlet, and in the other embodiment, the air flows across the bottom of the collector to pick up the material dropped thereinto. However, in either case, the collector of Smith et al. is not divided into discrete collection passages and all the material entering the collector exits the distributor through a single discharge tube. Thus, Smith et al. would not have a uniformity problem with distribution from discrete collection passages nor would it appear that his device would be operable were his collector divided into discrete passages, such as in the present invention.
Accordingly, it is the primary object of the invention described and claimed herein to provide an improved pneumatic dispenser of the type described wherein the material and propelling air are introduced to the collection passages at separate points.
A more specific object of the invention is to provide a plenum chamber adjacent the collector for receiving pressurized air and communicating therewith to introduce the air flow to the collection passages remote from the material collection openings of said passages.
A further specific object of the invention is to provide discrete air passages from the plenum chamber to each of the collection passages.
These and other objects of the invention are specifically met in a pneumatic material dispenser having a rotary member for carrying material on its periphery, a collector within the periphery having a plurality of axially spaced discrete material collection passages having openings near the periphery of the rotary member for gravitationally receiving material dropped from said rotary member, a plurality of discharge tubes in exclusive fluid communication respectively with each of the collection passages and having distal ends, and air supply means for delivering air to the collection passage ends of the discharge tubes at a higher pressure than the distal ends thereof to propel the material therethrough, the air supply means comprising a plenum chamber adjacent the collector supplied from an air source and air passage means establishing communication between the plenum and the collection passages remote from the material collection openings. Preferably, discrete air passages are exclusively downwardly directed respectively into one collection passage and have a reduction in cross-section from the plenum chamber to the collection passages.